Resolution of say 1080 x 720 means 1080 vertical lines of pixels and 720 horizontal line of pixels. This means a total of 777,600 numbers of pixels across the width and breadth of the screen. Now for Spatial resolution say for a 100ppi(considering 100 vertical lines per horizontal 1 inch, if I am correct) the width of the screen comes out to be 1080/100 = 10.8inches. But then how come we have TV screens much larger in size. Does that mean the aspect ratio of say a 30inches(width) TV screen has spatial resolution of just 1080/30 = 36ppi. Then how come the images are of such good quality.
In a phone also we find resolution of 1920 x 1080 then does it mean spatial resolution of the phone will always be better than that of equal resolution TV Screen, which is not apparent. What am I missing here?